Pulsed ElectroMagnetic Field Therapy (PEMFT) devices generate pulses of magnetic flux in order to affect an organism. These pulses may be used to reduce pain and inflammation, improve circulation and relax muscles. ElectroMagnetic pulses may also be used for brainwave entrainment, to generate free calcium ions in the body's cells, and to reestablish Circadian Rhythms and the body's internal biological clock. Investigations and observations of how the body perceives these pulses reveals longer duty cycles (the length of time the electromagnetic emitter is turned on) do not necessarily result in the body receiving more therapeutic effects. For the purpose of understanding how the body perceives electromagnetic pulses, the body of a mammal can be electrically emulated using a terminated copper wire coil inductor as shown in FIG. 1. Connecting Inductor 1, to channel 1 of Oscilloscope 2, and placing Inductor 1 near the electromagnetic pulse emitting Coil 3 connected to channel 2 of Oscilloscope 2 and a PEMFT device 4, results in waveforms shown in FIGS. 2 and 3. Gauss Meter 5 measures the relative magnetic flux emitted by Coil 3.
FIG. 2 shows the pulsing square Wave 6 and 7 used to drive the emitter Coil 3. This waveform is the most commonly used method to produce ElectroMagnetic Pulses. The lower half of FIG. 2 shows the typical resultant asymmetrical magnetic pulses as produced in Inductor 1, emulating the body's response to conventional, single polarity, or Monopolar, PEMFT devices. Positive magnetic Pulse 8 is observed in Inductor 1 when emitter Coil 3 is turned on (6). When emitter Coil 3 is turned off (7) the collapsing electrical field results in a negative magnetic Pulse 9 observed in Inductor 1, which is approximately half the strength of the positive magnetic Pulse 8. This uneven magnetic flux produces less than optimum therapeutic benefits.
Independent of the frequency used, Inductor 1 emulating the body of a mammal, only perceives, or uses, the initial charging pulse with duration of between 100 and 200 microseconds. The remaining time the pulse is active from the PEMFT device is not used by the body.
FIG. 3 depicts the usage of a reversing polarity (or Bipolar) H-Bridge driver for emitting Coil 3, found in more recent PEMFT devices, which results in even distribution of the resultant magnetic Pulses 12 and 13.
When the current flows in a positive direction 10 the resultant positive magnetic Pulse 12 is seen in Inductor 1. When the current is reversed and flows in the opposite direction (11) the symmetrically opposite Negative magnetic Pulses 13 are observed in Inductor 1. This symmetrical magnetic pulsing produces optimum therapeutic results, yet still results in unused energy to the body.
The width of the Positive or Negative magnetic Pulses 12 and 13 observed in Inductor 1 is limited to the ability of the inductor to store energy from the emitted magnetic flux by Coil 3. Research by the inventor has shown the effective maximum width of the induced pulses is 100 to 200 microseconds in duration. Additional On-Time of either pulse does not result in the body seeing or using additional energies from the PEMFT device. This is also the reason why extremely high frequencies (greater than 1 MHz) pass harmlessly through the body, as their duration is too short for the body to perceive any energy, unless the amplitude is high enough to cause ionization of water molecules as in the case of a microwave oven.
This pulse width can be shortened for high frequencies and lengthened for low frequencies in order to achieve an average pulsed duty cycle of 0.1% to 0.5% for frequencies from 1 cycle per second (Hertz or Hz) to 100 Hz, and from 0.5% to 1% for frequencies greater than 100 Hz but less than 500 Hz and from 1% to 2% for frequencies from 500 Hz to 1,000 Hz, and from 2% to 5% for frequencies from 1,000 Hz to 3,000 Hz.
Using conventional Pulse Width Management techniques to simply shorten positive Pulse 10 and negative Pulse 11 will result in odd waveforms when emitter Coil 3 collapses at the end of each shortened pulse, appearing to Inductor 1 as though the frequency has doubled with the creation of opposing asymmetrical magnetic pulses each time the emitter coil is turned off and the field collapses. This invention presents a novel and non-obvious method and apparatus to solve this problem, thus allowing the use of low-power batteries for light-weight, handheld or wearable PEMFT devices.